<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
	<body>
		<div id="header">
			header would be here
		</div>
		<div id="menu">
			menu would be heae
		</div>
	<div id="main_left">
		left sidebar
	</div>
	<div id="main_center" class="foobar">
		这儿用的嵌套搜索方法并不好，最好的办法是使用SimpleXML的xpath()方法，它使用正则表达式快速匹配元素属性。
	</div>
	<div id="main_right">
		right sidebar
	</div>
	<div id="footer">
		footer would be here
	</div>
	</body>
</html>